A standard luggage latch has a housing mounted on the piece of luggage and a latch body or slide displaceable in the housing between a latched and unlatched position and engageable only in the latched position with a latch component on the luggage lid to retain the latch component. A combination lock comprises a plurality of wheels that each have a peripheral row of numbers that can be viewed through a window of the latch housing. Respective rings rotationally coupled to the wheels have flats that are engaged by a keeper so that only when all of the flats are axially aligned can the latch component be disengaged from the keeper.
When such a latch is provided on a high-security transfer case such as is used by a courier to move documents or financial instruments between offices, security dictates that the combination only be known by the parties who are sending and receiving the package. In addition it is normally considered good practice to change the combination regularly in order to avoid that unauthorized persons gain access to the contents of the security case.
For the main office, keeping track of the numerous combinations of the various transfer cases is a significant nuisance, especially when they are changed every time there is a critical personnel change at a branch office. This is compounded by the fact that it is normally essential to know the current combination in order to be able to reset it.